Though they live on different continents, all the fluorescent mammals the Northland team has studied have something in common: They don’t come out much during the day. The fluorescent species the scientists found are either nocturnal—active mainly at night—or crepuscular—most active at dawn and dusk. When it’s darker out, UV light emitted by the sun or reflected off the moon isn’t drowned out by visible light like it would be in the daytime, says Martin. That could make fluorescent patterns more likely to show up.
As with other fluorescent animals, being able to glow could help mammals communicate with other members of their species or blend in with their surroundings. To find out for sure, scientists would need to observe their behavior in the wild. That’s difficult to do with animals that hide during daylight hours, says Olson. But he and his colleagues hope that other scientists will pick up where they left off and discover more about mammals that glow.
For Martin, who first noticed the fluorescent flying squirrel in his backyard, the project goes to show what can come from curiosity. Kohler, who is now a graduate student at Colorado State University, agrees. “It’s made me realize that there’s so much that is yet to be discovered,” she says. “To see the secrets that nature is hiding, sometimes all it takes is looking at things in a new light.”